Comparison of soil respiration among three different subalpine ecosystems on eastern Tibetan Plateau, China

The pattern of soil respiration and its responsible factors are still unclear in subalpine ecosystems. In this study, we used a static chamber system to measure soil respiration in a primary Abies fabri (Masters) Craib forest, a secondary A. fabri forest and a clear-cut land on Gongga Mountain, east of Tibetan Plateau in China. Our results showed there were substantial diurnal and temporal variations in these three subalpine ecosystems. The diurnal coefficient of variation (CV) of soil respiration was lowest in primary forest (20.5%), and highest in clear-cut land (40.4%). Diurnal patterns of soil respiration were generally associated with soil temperature at 5 cm for all the three systems. The temporal CV was lowest in secondary forest (55.6%), and highest in clear-cut land (82.8%). Soil temperature at 5 cm depth was the major factor controlling 55-61% of temporal variation of soil respiration. The temperature sensitivity (Q10 value) was higher in clear-cut land (Q10 = 6.7) than that in primary forest (3.7) and secondary forest (3.0), indicating that soil respiration in clear-cut land was more sensitive to temperature change. Annual soil respiration was 3330.2 g carbon dioxide (CO2) m(-2) year(-1), 2358.9 g CO2 m(-2) year(-1) and 4162.8 g CO2 m(-2) year(-1) for primary forest, secondary forest and clear-cut land, respectively. Our findings provided valuable information for understanding the effect of forest ecosystem change and land management on soil respiration in high-elevation subalpine ecosystems.